Electric horn



June 20, 1944. O LUCAS I 2,351,690

ELECTRIC HORN Filed May 25, 1942 I i/ 116101 61 Oliver-j mews By MPatented June 20, 1944 ELECTRIC HORN Oliver Lucas, Birmingham, England,assignor to Joseph Lucas Limited, Birmingham, England Application May25, 1942, Serial No. 444,446 In Great Britain June 5, 1941 3 Claims.('01. 177-7) This invention relates to electrically operated soundproducing horns for use more particularly on motor vehicles and of thekind usually described as wind horns in which pulsations are produced ina column of air by an electromagnetically vibrated diaphragm.

The object of the invention is to provide an improved dual horn, that isa horn adapted to produce a combination of two tones of different pitch.

In the accompanying sheet of explanatory drawings, Figure 1 is asectional elevation of an electrically operated dual horn constructed inaccordance with the invention, and Figure 2 is a plan of the body partof the horn.

In carrying the invention into effect as shown, I employ a body part aof short cylindrical form and having in each of its two flat end faces adeep spiral groove b extending from the centre to the periphery. Theopen side of each groove 12 is enclosed by a flat cover plate having atits centre an aperture d situated opposite the inner end of the groove.The outer ends of the grooves 1) merge into adjacent portions of a shorthollow flared extension e which projects from one side of the body parta, and which is shaped like the larger end of a trumpet, the saidportions being separated from each other by a central longitudinalpartition I dividing the interior of the extension. The body part a andits extension e form two trumpet ortions of the horn, and the two airpassages formed therein, by the grooves b and the communicating portionsof the extension, are suitably designed to produce the required twotones of different pitch. The body part a and its divided extension emay be formed integrally with each other as a die-casting or moulding ofmetal or any other suitable material. To prevent access of dirt theouter end of the extension c has secured in or over it a grid q madefrom wire mesh, perforated metal or the like.

On the outer side of each of the cover plates 0 above mentioned ismounted a diaphragm g, and on the outer side of each diaphragm ismounted any convenient electromagnetic means h for vibrating thediaphragm, each such means being enclosed by a removable cover i. In theexample shown each electromagnetic means comprises a winding 7', a coreis, and a movable armature l, the latter being secured to the centre ofthe corresponding diaphragm g which at its periphery is attached to thebody part a in any convenient manner, Electric current is suppliedsimultaneously to the windings 9' through interrupters r, conductors mand terminals as n, the

latter being carried by an insulating support 0 on the side of the bodypart a. remote from its extension e.

For supporting the horn above described on a vehicle or in any otherposition the body part a is provided with an attachment lug p or anyother convenient means.

Whilst it is preferred to make the body part a and its extension e inone piece, it may be formed by two or more separate pieces adapted to besecured together to form a structure which is equivalent to theone-piece construction above described.

By this invention I am able to provide a single two-tone electricallyoperated horn of the kind specified in a very simple and convenientmanner. The invention is not however limited to the above examples assubordinate details of construction may be varied.

Having thus described my invention what I do claim as new and desire tosecure by Letters Patent is:

1. An electrically operated dual horn comprising in combination a bodypart having a spiral groove in each of a pair of opposite faces, meansenclosing the open sides of the grooves and having openings situatedopposite to the inner ends of the grooves, a hollow extension projectingfrom the side of the body part adjacent to the outer ends of the groovesand divided internally into two parts which form with the grooves twoair passages designed to produce tones of diiierent pitch, a diaphragmmounted over the inner end of each passage, and electromagnetic meanssituated at the outer sides of and adapted to vibrate the diaphragmssimultaneously.

2. An electrically operated dual horn as claimed in claim 1, in whichthe body part and the hollow extension are formed integrally with eachother.

3. An electrically operated dual horn comprising in combination a shortcylindrical body part having in each of its flat end faces a spiralgroove extending from the centre to the periphery, flat cover platesenclosing the open sides of the grooves, each plate having a centralaperture situated opposite to the inner end of the corresponding groove,a hollow extension projecting from one side of the body part and dividedinternally into two parts which form with the grooves two air passagesdesigned to produce tones of difierent pitch, diaphragms at. the outersides of the cover plates, and electromagnetic means situated at theouter sides of and adapted to vibrate the diaphragms simultaneously.

OLIVER LUCAS.

